Father's obesity may be linked to child's autism

Paternal obesity may increase a child's risk of developing autism spectrum disorders (ASD), according to a recent population-based study.

The findings, published in the journal Pediatrics, revealed that children with obese fathers (BMI over 30) had a 0.27 percent risk of developing ASD while a child born to a normal-weight father (BMI less than 25) had a 0.15 percent risk. What's more, children over 7 with obese fathers had double the risk of developing Asperger's disorder.

Previous studies had showed a mother's weight before pregnancy may also increase a child's risk for ASD by 67 percent.

"We were very surprised by these findings because we expected that maternal obesity would be the main risk factor for the development of ASD," Dr. Pål Surén of the Norwegian Institute of Public Health said in a statement. "It means that we have had too much focus on the mother and too little on the father."

It also shows that ASD may be inherited rather than developed after birth.

Lead researcher Surén and colleagues studied data from over 90,000 Norwegian children at 3, 5 and 7 years of age. ASD was diagnosed in 419 of the children, with 57 percent of the cases confirmed by a specialist.

In the sample, 22 percent of the mothers and 43 percent of the fathers were overweight. The team also considered education, age, smoking, mental disorders and the child's weight at birth.

Even though they found a link between obese fathers and children with ASD, it was too small for researchers to conclude a cause and effect relationship.

"We have a long way to go," Suren said.

"The potential effects should be further investigated through attempts at replication of our analysis, and, if these are positive, through genetic and epigenetic studies," the researchers told MedPage Today. "It should also be explored whether paternal overweight and obesity are associated with an increased risk of other neurodevelopmental disorders in children."